While convenient, the single-use coffee pods are exactly easily recycled. As America's culture of convenience continues to flourish, single-cup coffee makers have become increasingly popular among coffee drinkers. But beneath those expedient one-cup coffee pods lies a growing environmental problem. "These things aren't readily recyclable, if recyclable at all," said Darby Hoover, senior resources specialist for the Natural Resources Defense Council. "Anytime you've got this kind of small, single-use packaging option, especially when there are clearly alternatives, it just leads me to question why you would promote that system over another that works just as well for many applications." Approximately 13% of the U.S. adult population drinks a coffee made in a single-cup brewer every day, according to a 2013 study from the National Coffee Association. That's up from only 4% in 2010, said Joe DeRupo, director of communications for the NCA. Green Mountain Coffee Roasters Inc., which acquired Keurig in 2006 and has since become the largest manufacturer of single-use coffee brewers in the country, has been struggling with the recyclability of Keurig's K-Cups from the beginning. Like most single-cup coffee pods, K-Cups consist of a combination of plastic, aluminum, organic material (coffee grounds) and a paper filter. While all said items can be easily recycled separately, the K-Cup as a whole cannot be recycled on a municipal level. "It's that hybrid packaging that makes it very hard for traditional recycling companies," said Albe Zakes, global vice president of public relations at the recycling company TerraCycle. "If you think of something as simple as a chip bag for example, a chip bag is fully recyclable. The challenge is that it's both plastic and aluminum, a hybrid packaging, which is very common, especially in food and beverage." Since 2009, TerraCycle has partnered with various single-serve coffee manufacturers to provide recycling solutions for spent coffee pods. By teaming up with Tassimo, Mars Drinks, Nespresso and more recently Illy, TerraCycle has developed a customized take back program for each company that has helped divert millions of coffee pods from landfills across the country. "Over the last couple years, TerraCycle has already collected I believe 25 million coffee capsules of the various applications through all these programs," said Zakes. "As we expand with more companies, bringing Illy into the fold, we've really ended up in a place where we work with basically everyone except for the K-Cup." Despite reaching out to the company multiple times, TerraCycle has not been able to develop a relationship with Green Mountain, Zakes said. Green Mountain is experimenting with various materials for a new, recyclable K-Cup, though nothing is in production yet. "I know and I appreciate that Green Mountain has been trying to wrestle with ways to make its pods more environmentally sustainable pretty much the whole time that they've been offering them," said Hoover, the senior resources specialist for the NRDC. "But incinerating them instead of recycling them doesn't reduce the need to rely on virgin source materials to make oodles more of these disposable pods." The question remains whether the convenience of single-serve coffee systems is worth the overall environmental impact.